Two methods of universal rotation of steel plates in valve spheres
The valve ball is sealed and seated using PTFE or RTFE materials, and the operating temperature is generally maintained between -290 ℃ and 2000 ℃.
There are two ways to use the universal rotation method for steel plates in valve spheres:
The first method is to use the hydraulic force of the tailstock to press the flat circular material tightly onto the outer end face of the spherical core mold, rotate it together with the main shaft, and use a hydraulic profiling device to gradually shrink and deform the flat plate by spinning several times, attaching it to the core mold to obtain a hollow half valve ball body. Then, excess burrs are cut off and welding grooves are processed. Finally, the two half valve balls are welded together with argon arc welding to form the desired hollow valve ball blank.
The second method also uses a flat blank for general spinning, but the difference is that after spinning it into a hemisphere, a cylindrical semi-finished product needs to be spun out. Then, the semi-finished product is loaded into the inner hemisphere core mold, and the tail seat top rod with the same diameter is used to press it down. The spinning method is the same as the necking of the steel pipe, gradually shrinking (closing) the cylindrical section to form the other half ball, and the excess metal material at the closing is attached to the top rod. Finally, the excess part is cut off to obtain the desired overall hollow ball blank.
The advantages of the universal rotation method for steel plates in valve spheres are: convenient source of steel plates, lower price compared to steel pipes, and the ability to achieve a complete hollow structure valve sphere. Compared with the previous scheme of necking spinning for steel pipes, the disadvantage is that it requires two core molds, the spinning process is complex, the structure and control of the spinning equipment required are complex, and the equipment cost is high. However, from the perspective of economic benefits and product quality, this scheme is still the best solution.
